Aggregate formation natural organic matter

The three examples of the effects of pedochemical weathering on the surface structures in soil clays just described illustrate the complexity of the reactive solid materials in natural soils. To these examples can be added many others, including the formation of iron oxyhydroxide or calcium carbonate coatings on the external surfaces (as opposed to interlayer surfaces) of phyllosilicates, the development of thick envelopes of colloidal organic matter on aggregates of metal oxides and aluminosilicates, and the... 

Soil organics are also considered to be essential to the formation of stable aggregates in a wide range of soils. Physical properties of soil, such as structure and bulk density, are influence by the quantity and nature of complexes that form between organic and mineral matter. The physical characteristics of a soil are important to plant growth due to their effects on aeration, water penetration and retention, and mechanical impedance to... 

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